79 



Orbits and antennulary fossss very imperfect, hardly more perfect than in 

 Homola, and formed on somewhat the same plan as they are in the Dromidse. 

 That is to say, there is a shallow common orbito-antennulary fossa — into which, 

 however, the antennules fold transversely, and entirely below, not beside, the 

 eyes — and the lower boundary of this fossa is formed by the basal joint of the 

 antennule, the basal joint of the antenna, and an external tooth. The eyestalks 

 are moderately long, are slender and tapering, and do not nearly fill their region 

 of the orbit : the eyes are small. 



AntenniJes well developed, transversely folded on the inflated basal joint, 

 which is free and exposed from its origin. Antennal peduncles arising external 

 to, and in the same plane with, the antennules : the flagella long. 



Buccal opening much wider in front than behind, not nearly covered by the 

 short slender external maxillipeds : efferent branchial channels well defined, 

 anteriorly produced and patulous : epistome linear : the palp of the external 

 maxillipeds articulates with the apex of the narrow meropodite. 



Chelipeds unequal in the male, sub-equal in the female : first, second and 

 third pau-s of legs long, slender and compressed (the second pair the longest), 

 with long sabre-shaped dactyli. Last pair of legs reduced to feather-like rudiments, 

 arising close together, high up, almost on the back. 



Genital ducts of the male opening at a distinct tubercle on the base of the 

 fifth pair of legs, the tubercle being embedded in a notch in the posterior border 

 of the sternum. 



Six gills on either side. 



Ptenoplax notopus, Alcock and Anderson. 



Areliseoflat notopus, Alcock and Anderson, J. A. S. B. Vol. LXIII. pt, 2, 1894, p. 181, pi. ix. figs. 3, 3a-i. 

 Ptenoplaa notopus, Aloook and Anderaon, 111. Zool. Investigator, Crust, pi. xv. figs. 2, 2a-b. 



Carapace extremely flat and depressed, transversely oval, with the anterior 

 and antero-lateral margins slightly concave ; its surface punctate beneath a 

 shaggy reddish fur. 



The front proper is extremely narrow — about one-fourteenth the greatest 

 breadth of the carapace — and is deflexed with the tip free and horizontal, the 

 tip also being sHghtly expanded and bilobed just as in Macrophthalmus. 



The orbital borders of the carapace, which together are half the greatest 

 width of the carapace, are concave on either side of the front, each concavity 

 being interrupted near the middle by a small projection : the antero-lateral borders 

 are short and oblique, are broadly concave, and are rather acutely produced at 

 their junction with the anterior margin : the postero-lateral borders, which con- 

 stitute four-fifths or more of the lateral extent of the carapace, are convex, and 

 form a small tooth at their angular junction with the antero-lateral borders : the 



